Composition for electrolytes for electrical etching.



. {STATES PATENT QFEIOE.

.rosnrn n. wnnxs, or nupLEneE, rsnnsrnvmr'n, assrenon T0 .mcxson swnnxs,

. OF DELAWARE COUNTY, PENNSYLVANIA, AND

PHIA, PENNSYLVANIA, TRUSTEES.

' COMPOSITION r03 ELECTBDLYTES ron nnncrmonr. n ronme.

No Drawing.

for Electrolytes for Electrical Etching, of which the following is aspecification.

My invention has for its object the productlon of an improvedelectrolytefor use in electrical etching of metals.

The general subject matte to which thi invention relates is discuss inmy prior applications, Serial Numbers 88,362, 108,232, and 119,548,filed respectively April 1, 1916, July 8, 1916, and September 11, 1916.In

1 the first of said applications, I have disclosed a method, apparatus,and certain com positions for electrolytes intended to be used therein;in the second application, I have described andclaimed a process andcomposition, and in the third application, I have described and claimedcertain improved apparatus. The electrolyte which I shall herena'fterset forthis "adapted for use in the aforesaid processes, .andwith the aforesaid apparatus, although it is not necessarilylimitedthereto, and may be employed in other connections, and for other metalsor alloys of metals than those therein specifically described.

In the prior applications referred to, I

have set forth a method of etching plates inwhich a resistant image isproduced on a plate, either by means of ink or powder,

which is well known in the art, or by means of a special gelatin-a bumenenamel of my own invention. The plate so prepared is suspended in asuitable bath or solution and connected sons to form the anode terminalof a circuit supplied with current of suitable voltage to produce thedesired amperage or volume of current flow per unit area of the. anode.The-cathode terminal, which is also immersed in the bath or solution,may be of various t pes and of various materials. In my app ication Ihavedescribed carbon cathodes, and have set forth means for kee ing thesurface of the plate clean so that 1t shall be completely and uniformlyexposed to the electrolytic action of the current, and for keeping thecathodes clean, and for preventing. undercutting of the edges of theimage or lines on the plate. 1

Specification of Ietteralatent. Application filed Apri180, 1911. SerialNo. 185,474.'

Patented Sept. 2, 1919.

The problems to be met are different from thosepresented in the"electro-plating I RAYMOND MLWEEKS, 0F PHILADEL- current into or throughthe solution, which must be properly regulated, andthis to a muchgreater degree, of accuracy and uni; formity than is necessary'in theart of deposltion. In my experimental work, which has extended over aconsiderable period, and in thecourse ofwhich the present invention andthe others hereinbefore referred to have been produced, I have foundthat the compositipn of the electrolyte plays a very considerablepart,not only in the regulation of the action on-the plate, but in theuniformity of such action, and in maintainin safid uniformity forany-appreciable period 0 time.

into the chemical reactions'or the steps in transference of the metals,which take place with any particular composition, I may say generallythat I have found it necessary to provide a solution which shall have,first, the proper conductivity; second, a capacity for absorbing andtransferring the electrl- Without going into detail at this time, a

cally displaced metal from the plate without I soon becoming saturatedor cloggedthird, no tendency to foul or coat or form bubbles or spotsupon the plate, which would impede the rec passage of the current andthereby mar the engraving; fourth, no tendency, or a reduoedtendency, tofoul and form sludge upon the cathode surface in such mannerthat itcannot be readily re-, moved; and fifth, such elements and such a'balance of forces and properties that its efficiency willremain-unimpaired for a considerable period of time, and use.

The solution which I shall hereinafter set forth, and which has for itsprincipal active element an acetate or acetates, either alone or incombination with certain other substances, meets these conditions, andhas enabled me, by actual test, to produce as good results' with thelast plate of a lon' series, as with the first one, for example t e samedepth ofetching in the same length of time.

The present invention is correlated to and in most cases interchangeablewith the in.

ventions set forth in my companion applications executed of even dateherewith and my. prior applications Q Serial Numbers 159,776, 139,777and 159,778, all filed Aprll 4, 1917. The solution in the present casehas for its principal active" element an acetate or acetates-alone or incombination w th certain othersubstances.

trolytes are useful is very large, including all the metals specified inmy ,prior applications above referred to, and many others. i The metalsmost commonly employed in the engraving art are copper, brass, steel,nlc'k'el and zinc, and the plates are employed for printing, stamping,and for other purposes.

In additiom to. the engraving ofsteel pr ntingplates ,both' in reliefand intaglio, the manufacture of steel dies and plates for stampingmetals is, in itself, very important, and by my process, and with mysolutlens, I can produce such dies and plates in much less time, andwithmuch less expense, than 25 where they are cut by hand according to thepractice prior to this invention. Wherethe plates are'to be employed forprinting, my invention is specially important at the present time,because ofv the scarcit of high 3& grade paper, and .the necessity orhaving perfect printing plates in order to produce.

satisfactory results on .,the cheap grade of paper now commonlyemployed, because of,

such scarcity..- a

Electrolytes are prepared, for the greatest efliciency and economy, for.the particular metals to beetched'. Wherever practi: cable, acombination is used in which theplate to be etched is kept clean withoutwipdc icate work, as frequentwiping would,

' tend to injure the material of the image 1 In coarse work, this isrelatively immaterial, and an electrolyte involving wipin of the whereit is cheaper to prepare, or produces a speedier action. The cleanlinessof the cathode is next preferable, as involving less labor in keepingclean, or as rendering that portion of my apparatus having movablebrushes unnecessary, with a consequent sav-- ing in power used thereby.For thereasons stated, some of my formulae do not give both a cleancathode and a clean anode.

The various use of acetates with other salts and with\ or without acids,is in some instances to secure anode or cathodeplate, cleanliness'orboth, and to obtain" electrolytes which shall form the best chemicalcombinations in themselves andv with the anode, shall-have the longestlife, and produce the smoothest etching, i 6., to avoid rough grainyetching on either the sides 'of the lines or the bottom, and further,"to secure a deelisir'able speed which will admit of commer- 1 The classof metals with which these elec-" m This is especially requisite invery.

plate may easily be used, and woul be used .cial etching of the various.metals with prac tically the same electric. current density.- The valueof this'last is obvious, particularly where one dynamo or battery set isemployed to supply current for the etching of different 7 metals inseparate tanks without the employment of resistance. An acid conditionis desirable in all electrolytes to give stability to the same and toincrease the conductivity. If the-constituent salts -do not render theelectrolyteacid or suificiently acid for th'ese purposes, an" acidshould be added. Some excellent electrolytes would promptly separateunder electrolysis and promptly become useless were it not for theaddition of the acid. Even if this does not occur the life of the'electrolyte is shorter without acid and its conductivity less.= .Furtherin many cases the presence of an acid prevents precipita- 8 tions in'theelectrolyte or on the-cathode or on the anode or performs two or all ofthese functions.

In some combinations where the ordinary acids do'not keep thecathode orthe anode clean or prevent precipitatioils in the bath,

this'may 1n :some instances b partly or wholly accomplished by theaddition of a chromium salt, or by' What .is generally termed chro'micacid. (usually potassium dichromate solution acted upon by sulfuricrium, cadmium, calcium, chromium, cobalt,.

manganese, f

copper,firon lead, magnesium,

frel, potass um, sod1um, uranium mercury, nic

and zinc,

While the essence of the invention is the use of asuitable acetate, Imay and do em- 5 ploy more than one, in combination, when required, butit is obvious that only thosewhich will properly mix or combine can besimultaneously employed.

WithNahe acetates- I may combine other salts with or without an acid. Imay also employ as an additional element, a small quantity of aperchlorid, such as they perchlorid of iron, containing an excess ofacid. This may be used in lieu of one or more of the foregoing acetates,and in such caseyno other acid is usually necessar The prm-' cipalfunction of the separate acid, if added,

is to increase the conductivity and prevent decrease in current densityand tends in most cases to keep the face cf the plate clean and toprevent disintegration of the solution;

. As an example of a solution in which an acetate'and an acid areemployed, I may.

give-the following:

Magnesium acetate i v60 grains.

Water -1 2 oz.

Muriatic acid 1 oz. '7

As an example of an acetate, a chromium salt and an acid, I may give thefollowing: 4 Iron acetate saturated aqueous A solution 2 oz. Chromiumsulfate; 60 grains. Water; 2 oz.

Muriatic acid C. P 1; oz.

As an example of an acetate, anoxalate and an acid, I may give thefollowing:

Sodium acetate 120 grains.

Water J --g. 2 oz. Potassium oxalate 60 grains. Water 2 oz. Muriaticacid C. P 1} oz.

' As an example ofan acetate, a tartrate and an acid, I may give thefollowing:

Ammonium acetate; 180. grains. Ammoniumtartrate 120 grains.

.Water 4 oz.

Nitric acid 0. P

As an example of an acetate, a chlorid and an acid, I may give thefollowing;

Uranium acetate saturated aqueous solution i 2 oz.

Sodium chlorid in water to test 20 Muriatic acid C. P

Baum 2 oz. Muriatic acid G. Pr, ..L- if oz.

As an example of an acetate, a nitrate and an acid, I may give thefollowing:

Cadmium acetate i 240 grains. Ammonium nitrate 240 grains. Water 4 oz.

- As an example of an acetate, a borate, an

oxalate and an acid, I may give the follow- Ammonium acetate 120 grains.

Potassiumborate 120 grains.

Water 4 oz.

Iron oxalate saturated aqueous solution 1} oz.

Muriatic acid 0. P oz.

It is to be noted that in the claims where I mention an acetate, aborate, a chlorid, a

sulfate, a tartrate, a nitrate or an oxalate,

or a combination of any of these without mentioning a particular metal,"I include in that'tcrm one or more of the salts from the same acid,that 15,,one. or more acetates,- one or more borates, etc; Y

"Having thus described my invention what I claim and-desire to secure byLetters Patent is: a l

1. In electrolytic etching, an anode carrying a resistant image to beetched, in combination with an electrolyte comprising one or more of theacetates of ammonium, barium,

'cadmium, calcium, chromium, cobalt, copper,

iron, lead, magneslum, manganese, mercury, nickel, potassium, uramum orzinc.

2. In electrolytic etchlng, an anode carrying a resistance image to beetched, in combination with an electrolyte comprising one or more of theacetates of ammonium, barium, cadmium, calcium, chromlum, cobalt,

copper, iron, lead, magnesium, manganese,

mercury, nickel, potassium; uranium or zinc with an acid.

3. In electrolytic etching, an anode carrying a resistant image to beetched, in combination with an electrolyte comprising one I with aborate, a chlorid and an acid.

- 5. In electrolytic etching, an anode-carrying a resistant image to beetched, in combination with an electrolyte comprising one or more of theacetates of ammonium, barium, cadmium, calcium, chromium, cobalt,copper, iron, lead, magnesium, manganese, mercury, nickel, potassium,uranium or zinc witr a borate, a chlorid, a sulfate and an M1 ing aresistant image to be etched, in combination with an electrolytecomprising one or more of the acetates of ammonium, bari- 6. Inelectrolytic etching, an anode carry-j um, cadmium, calcium, chromium,cobalt,

copper, iron, lead, magnesium, manganese, mercury, nickel, potassium,uranium or zinc with a borate, a chlorid, a sulfate, a tartrate and anacid.

7. In electrolytic etching, an anode carryinga resistant image to beetched, in combination with an electrolyte comprising one or more of theacetates of ammonium, barium, cadmium, calcium, chromium, cobalt,copper, iron, lead, magnesium, manganese, mercury, nickel, potassium,uranium or zinc with a borate, a (chlorid, a sulfate, :1. tartrate, anitrate and an acid.

8. In electrolytic etching, an anode carrying a resistant image to beetched, in combination with an electrolyte comprising one or more of theacetates of ammonium, bani-- um, cadmium, calcium, chromium, cobalt,copper, iron, lead, magnesium, manganese,

mercury, nickel, otassium, uranium or zinc with a borate, a c lend, asulfate, a tartrate,

a nitrate, a-n oxalate and an acid.

9. In electrolytic etching, an anode carry- 11m, cadmium, calcium,chromium, cobalt,

copper, iron, lead magnesium, manganese, mercury, n1ckel,-potass1um,uranium'or zmc with a'borate, a; chlori-d, a sulfate, a tartrate,

a, nitrate, anoxalate, a chromium salt other than the acetate, 'borate,chlorid, nitrate, su-l-l fate or-tartrate and an acid.

In testimony whereof I afiix my signature.

J )SEPH' H. WEEK S.

